<form method="post" action="<?php echo $PHP_SELF?>">
This means the form is processed in the same page.
You should make 2 more pages to avoid resubmitting the form when you refresh the page.
You should cut&paste the database insertion in a new page, which should be declared as action in the first page.
<form method="post" action="second.php">
Then, once the data is inserted in the database, you redirect to the third page, where you should cut&paste the database look up and copy&paste the form filled out of database.
<script language="Javascript">document.location.replace('third.php');</script>
I hope I have explained myself a bit more